Parental care is critical to child survival and healthy human development, yet we know little about how the brain controls parental care and about biological sources of variation in this behavior. The proposed research uses two species of Peromyscus mice that differ greatly in their parental care to identify genes and neuronal mechanisms that regulate parental care in mammals. To identify genetic variants, the candidate will perform a genetic analysis using a large cross between the two species. To define brain regions involved in parental care, the candidate will compare brain-wide patterns of neuronal activity between mice caring for their pups and mice ignoring them. He will then analyze the genes expressed in the identified brain regions to find genes that differ between the species. Identified genes that are common to both the genetic analysis and the gene expression analysis will point to specific molecular pathways relevant to parental care. These pathways will be further tested with pharmacology and transgenics techniques. Candidate and his career goals. The candidate, Dr. Andrs Bendesky, has a strong background in quantitative genetics and neuroscience, having spent his PhD identifying genetic variants that modulate decision-making and characterizing how these variants modify neuronal circuits. Dr. Bendesky's long-term career goal is to develop an independent research program devoted to understanding the causes and mechanisms of variation in behavior between individuals. He is particularly interested in understanding how genetic variation modifies the brain to alter behavior. The goals of this proposal are to define the genetic elements responsible for differences in parental care between two closely related species of wild mice and to characterize the neurobiological pathways involved in such variation in behavior. Key elements of the research career development plan. The research proposed for the mentored phase of the proposal will be conducted in the laboratories of Dr. Hopi Hoekstra and Dr. Catherine Dulac at Harvard University. Dr. Hoekstra is an expert in Peromyscus biology, behavior and genetics. Dr. Dulac is an expert in the neurobiology of social behaviors, including parental behavior. Their expertise optimally synergizes to guide the research proposed here. The candidate has an Advisory Committee composed of Dr. Elizabeth Spelke (Harvard), a distinguished cognitive developmental psychologist, and Dr. Rudolf Jaenisch (MIT, Whitehead Institute), an expert in animal genome manipulation. Both mentors and advisors will guide the candidate in his research and in the transition to an independent research career. The environment at Harvard and in the Hoekstra/Dulac laboratories is spectacular, providing excellent facilities and all the needed equipment for the proposed research. It is an ideal training place: remarkable seminars, opportunities to present research progress and receive feedback, and resources to help transition to independence.